x-3/4x=0.4

Solution for x-3/4x=0.4 equation:

x-3/4x=0.4

We move all terms to the left:

x-3/4x-(0.4)=0


Domain of the equation: 4x!=0

x!=0/4

x!=0

x∈R


We add all the numbers together, and all the variables

x-3/4x-0.4=0

We multiply all the terms by the denominator


x*4x-(0.4)*4x-3=0

We multiply parentheses

x*4x-1.6x-3=0

Wy multiply elements

4x^2-1.6x-3=0

a = 4; b = -1.6; c = -3;
Δ = b2-4ac
Δ = -1.62-4·4·(-3)
Δ = 50.56
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1.6)-\sqrt{50.56}}{2*4}=\frac{1.6-\sqrt{50.56}}{8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1.6)+\sqrt{50.56}}{2*4}=\frac{1.6+\sqrt{50.56}}{8}
$